Thermoelectric blanket



July 11, 1961 c. G. SUITS THERMOELECTRIC BLANKET 2 Sheets-Sheet 1 FiledJuly 1, 1959 inventor: Chauncey G. Su/i's, b Ma. 0% /-//'s Attorney.

July 11, 1961 c. G. SUITS 2,991,627

THERMOELECTRIC BLANKET Filed July 1, 1959 2 Sheets-Sheet 2 Jnventor':Chauncey G. Suits,

by M4 32 His Attorney.

United States Patent 2,991,627 THERMOELECTRIC BLANKET Chauncey G. Suits,Schenectady, N.Y., assignor to General Electric Company, a corporationof New York Filed July 1, 1959, Ser. No. 824,281 8 Claims. (Cl. 62-3)This invention relates to a thermal device and more particularly to acooling and heating blanket which may be placed in close proximity to anobject, such as a human body, for removing excess heat therefrom.

The comforting and therapeutic effects of maintaining the human body inan environment of a prescribed range of temperatures are Well known andconsiderable effort has been directed toward the provision of means toaccomplish this end. In particular, the advantages to be derived byremoving excess body heat during sleeping hours are well knowHereto-fore, proper cooling of sleeping environs such as a room or anentire building has been provided by suitable air conditioning apparatusinvolving refrigeration machinery or simply large air circulating fans.Installations of these types are large, bulky and expensive in initialcost, as well as being difiicult and expensive to operate and maintain.

Alternate schemes for providing cooling of a human body during sleephave included thermal blankets utilizing the circulation of a liquidcoolant through suitable flexible tubes embedded therein. These,however, have disadvantages in that they are heavy and require complex,inconvenient and often expensive auxiliary apparatus. Moreover suchprevious blankets present serious safety hazards and destruction ofblanket and bedding from leaks that may occur in cooling tubes.

It is, therefore, a principal object of my invention to facilitate thecooling of objects, particularly of the human body during periods ofinactivity by the provision of a cooling blanket obviating the use ofcooling tubes containing a circulating cooling liquid or othercomplicated auxiliary equipment.

It is another object of my invention to facilitate cooling of the humanbody, particularly during sleep, without the necessity of cooling atleast an entire room.

It is still another object of my invention to facilitate controlledcooling of the human body particularly during sleep, by simple andinexpensive means.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which I regard as myinvention, the invention will be better understood from the followingdescription taken in connection with the accompanying drawings in which:

FIGURE 1 illustrates in perspective view, partially cut away, an entireblanket according to my invention, together with heat removing means andcontrol apparatus therefor,

FIGURE 2 shows in detail a single Peltier junction unit and thecircuitry necessary for forming a component of the cooling apparatus ofthe invention,

FIGURE 3 is a detailed view in perspective showing the arrangement ofcooling apparatus components forming part of the blanket shown in FIGURE1,

FIGURE 4 is an enlarged cross-sectional elevation, the details ofconstruction of the blanket in FIGURE 1 and in particular showing thedetails of a modified arrangement of Peltier unit interconnectionsadjacent to air passages therein,

FIGURE 5 is an enlarged, cut-away perspective view, illustrating ingreater detail, the arrangement of difierent parts of the blanket as awhole, and

FIGURE 6 illustrates in perspective another embodiment of the inventionshowing the construction and interconnection of cooling units of theblanket.

In accordance with my invention, I avoid the aforementioneddisadvantages of prior cooling apparatus by the provision of a coolingblanket in which is disposeda plurality of Peltier junctions throughwhich direct electrical current is passed to obtain cooling. The portionof each junction in which cooling occurs is disposed on a side of theblanket which isplaced adjacent to the body and the portions of thePeltier junction in which heat is generated are disposed on the side ofthe blanket remote from the cool side and are exposed to either ambientair or to confined regions through which ambient air is circulated byforce, to increase the removal of heat from the hot junction. Thecombined effects of the many Peltier junctions is to provide a largecontinuous area on one side of the blanket which is cooled and which mayabsorb excess body heat while the combined heat dissipating portions ofthe Peltier junctions together with the circulation of ambient airthereover, facilitates the complete removal of such excess heat from theother side of the blanket. To provide flexibility in all planes to theblanket, the portions of the Peltier material are conductively joined byflexible metal straps which may, for example, be woven wire. Althoughthe blanket of my invention finds its greatest utility in its coolingfunction it is also within the purview of my invention to reverse theeffect of the Peltier junctions to produce heat by the blanket to warmobjects adjacent thereto as the occasion may require.

Referring now more particularly to FIGURE 1 of the drawings, 10represents generally the entire blanket of my invention which includes apair of opposed portions 12 and 14 which may be of a suitable clothmaterial interiorly rubberized as at 15 and joined together at one endby a selvage 16 and at the other end being rounded and folded back at 18to form a pocket 29 with connecting sides as at 22, conformable with oneend of a mattress to form a contour-type blanket.

As shown in FIGURES 4 and 5 of the drawings as well as in FIGURE 1,between the cloth portions 12 and 14 there is disposed a layer offlexible material 24 having electrical and thermal insulating propertiesand may, for example, be foam rubber. A plurality of spaced grooves suchas 21 and 23 are formed along the length of the material 24 foraccommodating a like plurality of rows of Peltier cooling junctions asshown at 26 and 28. The rows of cooling junctions are embedded in thematerial 24 and one side of each junction unit is adjacent to the cloth12 on the one side of the blanket. The grooves are separated by walls ofthe material 24, as shown at 25 and 27 in FIGURES 4 and 5, and thenumber of such rows is such as to provide substantial coverage of theentire area of the blanket. Thus, a groove is near each portion of theside 12 of the blanket.

As shown more clearly in FIGURE 2 of the drawings showing arepresentative Peltier junction unit and its electrical circuit, eachPeltier junction includes a pair of members as at B0 and 32, of Peltiermaterial joined at one end by a conductive member as at 34. As analternative embodiment of my invention, the members may be in directcontact with each other without the use of a member as 34, care beingtaken to provide a surface of sufficient contact area between members,as an example, one or both of these members may be of L-shape such thatthe portion of the unit comprising the member 34 in FIGURE 2, could be apart of either of the Peltier members or portions of this connectingmember may be integrally formed and be of respective Peltier materials.One of the members of Peltier material of each junction is of p-typesemiconducting material and the other is of n-type semiconductingmaterial. In the circuit of the Peltier junctions, a direct potential,as represented by battery 36, is applied across the ends of the Peltiermaterials remote from the joining member 34. In accordance with the wellknown Peltier effect, when the potential of the p-type member ispositive with respect to the potential of the n-type member, causing acurrent flow through the junctions, a heat transfer occurs in thePeltier materials whereby the ends joined with member 34 are cooled withrespect to their initial temperature and the ends remote from thesejunctions are heated. Many materials suitable as Peltier materials 30and 32 are known and they may, for example, be p-type and n-type bismuthtelluride, respectively.

The extent of cooling produced at each junction is affected by thelength of the Peltier members, with greater lengths, less than apredetermined value at which maximum effect is achieved, producinggreater cooling. In accordance with my invention, the Peltier membersare of a length at which efiective cooling is produced and may bedivergent away from each other as shown in the drawings to establishwide grooves in which disposed, the unoccupied portions of which providechannels enlarged in width for circulating a fluid coolant.

The potential required to be applied between the ends of the Peltiermembers is determined by the lengths of the Peltier members and theextent of cooling desired. Under the circumstances herein, whereinblanket thicknesses of the order of A1 inch are contemplated, thepotential difierence across each Peltier junction unit may be a fewvolts as, for example, 2 volts. Thus, for use with the conventionalpower supply in the usual dwelling, viz., a 115 volts, 60 cycle supply,with a suitable rectifier, the rows of Peltier junctions in the blanket1t comprise groups of junction units connected in series circuitarrangement as shown in FIGURE 3, for example. A suflicient number ofsuch units are so connected to reduce the potential difference acrosseach unit to a value at which such unit is usefully operable. As shownin FIGURE 3, the Peltier junction unit 37 is connected in series withthe next adjacent unit 38- by a connector bar 40 and the next adjacentunit 41 by a bar 42, etc. These connector bars may be rigid; however,for imparting flexibility to the blanket, flexible conductive straps, asshown at 44 and 46 in FIG- URE 3, may be substituted at spaced locationsfor certain of the rigid bars. In accordance with another embodiment ofmy invention, as shown in FIGURE 6, even further flexibility may beimparted to the blanket by providing flexible, conductive straps foreach series connection between Peltier junction units.

For supplying electrical current to the Peltier junction units, arectifier, preferably of a well-known dry type such as a selenium type,not shown, may be provided and contained in the housing of anelectrically driven blower 48. An electrical cord and plug 50facilitates connection to the usual house current supply for operatingthe Peltier junctions and a suitable rheostat 52 with control knob 53may be coupled to the supply source for controlling the current flow inthe junctions and therefore, for controlling the extent of cooling.

As hereinabove explained, the ends of the Peltier materials remote fromthe connecting member are raised in temperature during operation of theblanket. For dissipating the heat so produced, air channels as at 54 and56 are established adjacent to such ends and one cloth side, 14, of theblanket as shown in FIGURE 4 of the drawings. Each channel is furtherconfined by walls of insulating material 24 between the grooves. Eachair channel above each row of junctions is in communication With eachadjacent air channel at its respective ends, thus forming a continuousair path through the blanket above the rows of junctions. To enhance thecooling of the heated portions of each junction, ambient air iscirculated through the air path so formed, by blower 48, whichdischarges air through a flexible tube 55 into an intermediate point ofthe continuous air path described. Such air is divided and follows twopaths of substantially equal length through the air channels and isdischarged at respective ports 57 and 58 at opposite sides of theblanket and near one end thereof. For controlling the rate of such airflow, the motor of blower 48 may be provided with a suitable rheostatcontroller, operated by a knob 60.

In accordance with another feature of a modification of my invention, asshown in FIGURE 4 of the drawing, the bars interconnecting the Peltierunits may be made wider than the semiconducting members with which theyinterconnect so as to overhang as shown at 62, for example. With suchconstruction, the heat dissipating area of the units is increased toimprove the effectiveness and efliciency of the blanket.

While the present invention has been described by reference toparticular embodiments thereof, it will be understood that numerousmodifications may be made by those skilled in the art without actuallydeparting from the invention. 1, therefore, aim in the appended claimsto cover all such equivalent variations as come within the true spiritand scope of the foregoing disclosure.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A thermal blanket comprising a pair of spaced layers of clothmaterial and a layer of flexible non-conductive, foam rubbertherebetween, said foam rubber having a plurality of grooves thereinseparated by ridges of said foam rubber and a plurality of Peltierjunction units in each groove, each unit including a member of p-typesemiconducting material and a member of n-type semiconducting materialand means adjacent a first side of said blanket establishing conductivecontact between said semiconducting materials of each unit, meansserially connecting the Peltier units in each groove and including aflexible strap conductively connected between the p-type member of oneunit and the n-type member of the next adjacent unit in one direction,means serially connecting the pluralities of Peltier junction units inthe several rows with p-type members conductively joined to n-typemembers in the respective grooves, means establishing an electroncurrent from the n-type member to the p-type member in each unit, theheight of said units being less than the depth of said grooves to form apassage between said units and the second of said cloths and means forcirculating ambient air through said passage to absorb and remove heatfrom the portions of said uni-ts remote from said first side wherebycooling of said first side of said blanket occurs.

2. A thermal blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said cloth layers; a plurality ofPeltier junction units distributed in and supported by said layer offlexible material each Peltier junction unit including a member ofP-type conductivity semiconductive material, a member of N-typeconductivity semiconductive material and a conductive joining member incontact with an end of each of said semiconductive members and beingadjacent a first one of said cloth layers; flexible air passage meansenclosing the ends of said P-type and N-type members remote from saidjoining member; means controllably establishing a flow of electroncurrent from the N-type member of one Peltier junction to the P-typemember of an adjacent Peltier junction unit said means further providingfreedom of movement therebetween in all planes; and means forcirculating ambient air through said flexible air passage means.

3. A thermal blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said cloth layers; a plurality ofPeltier junction units distributed in and supported by said layer offlexible material, each Peltier junction unit including a member ofP-type conductivity semiconductive material, a member of N-typeconductivity semiconductive material and an electrically conductivemember joining one end of each of said P-type and N-type members;flexible air passage means integral with said layer of flexible materialfor enclosing the ends of said semiconductor members remote from saidjoining member; means controllably establishing a flow of electroncurrent from each N-type member of one Peltier junction unit to theP-type member of an adjacent unit said means further providing freedomof movement therebetween in all planes; and means for circulatingambient air through said flexible air passage means to absorb and removeheat from the ends of said junction units enclosed therein.

4. A thermal'blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said cloth layers; a plurality ofPeltier junction units distributed in and supported by said layer offlexible material, each Peltier junction unit including a member ofP-type semicondnctive material, a member of N- type semiconductivematerial and a conductive joining member in contact with an end of eachsaid semiconductor member and adjacent a first one of said cloth layers;flexible air passage means enclosing the ends of said semiconductormembers remote from said joining members, said air passage means beingenclosed on two sides by portions of said flexible material and on thetop by the other of said cloth layers; means for controllablyestablishing a flow of electron current from the N-type member of onePeltier junction unit to the P-type member of an adjacent unit, saidmeans including flexible connecting means to provide freedom of movementbetween said Peltier junction units in all planes; and means forcirculating ambient air through said flexible air passage means.

5. A thermal blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said cloth layers; a plurality ofPeltier junction units distributed in and supported by said layer offlexible material, each Peltier junction unit including a member ofP-type semiconductive material, a member of N- type semicondnctivematerial and a conductive joining member in contact with an end of eachsemiconductor member and adjacent a first one of said cloth layers; aplurality of flexible air passage means enclosing the ends of saidsemiconductor members remote from said joining members, each of said airpassages being confined on two sides by walls of said flexible material,on top by the other of said cloth layers and in communication with eachadjacent air passage at its respective ends; means for connecting theend of each except one N-type member remote from said joining member toan end of a P-type member remote from said joining member otherwiseunconnected, said means providing electrical conduction between saidsemiconductor members and freedom of movement therebetween in allplanes; means for applying a direct current potential across theunconnected ends of said semiconductor members establishing current flowthrough said units in series; and means for circulating ambient airthrough said plurality of air passage means to absorb and remove heatfrom the ends of said semiconductor members enclosed therein.

6. A thermal blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said layers of cloth material,said flexible material having a plurality of grooves therein separatedby ridges of said flexible material; a plurality of Peltier junctionunits disposed in each groove, each unit including a member of P-typesemicondnctive material, a member of N- type semicondnctive material andmeans adjacent a first side of said blanket establishing electricalcontact between said P-type and said N-type member, the height of saidunits being less than the depth of said grooves to form a passagebetween said units and the second of said cloth layers; means seriallyconnecting the Peltier units in each groove and including a flexiblestrap electrically connected between the P-type member of one unit andthe N-type member of the next adjacent unit in one direction; meansserially connecting the pluralities of Peltier junction units in theseveral grooves with P-type members conductively joined to N-typemembers in the respective grooves; means establishing an electroncurrent from the N-type member to the P-type member in each unit; andmeans for circulating ambient air through the passage formed betweensaid units and the second of said cloth layers to absorb and remove heatfrom the portions of said units remote from said first side wherebycooling of said first side of said blanket occurs.

7. A thermal blanket comprising: a pair of spaced layers of clothmaterial; a layer of flexible material having electrical and thermalinsulating properties disposed between said layers of cloth material,said flexible material having a plurality of channels therein confinedby walls of said flexible material and in communication with eachadjacent channel at its respective ends; a plurality of Peltier junctionunits disposed in each of said channels each including a member ofP-type semiconductive material, a member of N-type semicondnctivematerial and means adjacent a first cloth layer establishing electricalcontact between an end of said P-type member and an end of said N-typemember, said semicondnctive members being divergent away from each otheron the respective ends remote from said contact; means controllablyestablishing a flow of electron current through each of said Peltierjunction units from the N-type member to the P- type member, said meansincluding flexible connecting means to provide freedom of movementtherebetween in all planes; and means for circulating ambient airthrough said plurality of channels for removing heat from the divergingends of said semiconductor members adjacent said second cloth layer.

8. A thermal blanket comprising: a pair of spaced layers of interiorlyrubberized cloth material; a layer of flexible material havingelectrical and thermal insulating properties disposed between saidlayers of cloth material, said flexible material having a plurality ofgrooves therein separated by ridges of said flexible material; aplurality of Peltier junction units in each groove each including amember of P-type semicondnctive material and a member of N-typesemicondnctive material in electrical contact with each other, theheight of said units being less than the depth of said grooves to form apassage between said units and one of said layers of cloth material;means serially connecting the Peltier junction units in each groove andincluding a flexible strap electrically connected between the P-typemember of one unit and the N-type member of the next adjacent unit inone direction; means for establishing an electron current through eachPeltier junction unit from the N-type member to the P-type member; andmeans for circulating ambient air through said passage formed betweensaid Peltier junction units and said one of said cloth layers to removeheat from the ends of said semiconductor members adjacent said passage.

References Cited in the file of this patent UNITED STATES PATENTS413,136 Dewey Oct. 15, 1889 2,110,022 Kliesrath Mar. 1, 1938 2,504,308Donkle Apr. 18, 1950 2,749,716 Lindenblad June 12, 1956 2,870,610Lindenblad Jan. 27, 1959 2,93 8,356 McMahon May 31, 1960

